基于相空间重构和核主分量的水声信号增强

多径衰落是水声信道的主要特征,利用多径衰落信道具有的混沌行为,提出一种新的抗多径干扰的方法.建立基于混沌相空间的水声信道模型,利用核技巧φ(x)·φ(y)=k(x,y),通过核主分量分析提取相空间数据中累积贡献率达到90%的非线性核主分量,然后利用核主分量逆向投影回原相空间,通过去掉噪声干扰等次分量,提高水声衰落信号的信噪比.基于实测水声数据的仿真实验结果表明,该方法能将chirp水声信号信噪比提高7.76 dB,达到对多径衰落水声信号增强的目的. 

Underwater Acoustic Signal Enhancement Based on Phase Space Reconstruction and KPCA

Multipath fading is the main feature of underwater acoustic channel. Considering the chaotic behavior of multipath fading channel, a new method was proposed to resist the multipath interference. Firstly, an underwater acoustic channel model was established based on chaotic phase space. On the basis of this model, through kernel principal component analysis(KPCA) with nuclear techniques φ(x)·φ(y)=k(x, y), nonlinear kernel principal component could be extracted from the spatial data, which cumulative contribution rate could achieve 90%. And then, the kernel principal component was used to reverse project the spatial data back to the original phase space, and the noise component was removed to improve the noise ratio of acoustic signal. The simulation results and the measured acoustic data show that this method can improve the noise ratio of acoustic signal to 7.76 dB, and can achieve the goal of enhancement of multipath fading underwater acoustic signal.